The present invention relates to a semi-permanent hair dye composition and a process for its use on hair.
Many compositions for dyeing human hair are known. These are applied directly to the hair by, for example, squeezing dye liquid through a nozzle, or spraying a dye composition, or applying the dye by any other conventional method. Often hair dyeing involves first applying a dye composition and then fixing it by an oxidation step using peroxide or the like.
U.S. Pat. No. 5,964,226 to Joan Lasker Sobel (which is incorporated herein by reference thereto) describes a unique hair product application system wherein hair coloring composition is maintained in a reservoir provided with an applicator tip extending from within the inside of the reservoir to absorb hair coloring solution and to deliver it to the outside of the reservoir by capillary action to an applicator tip for applying the coloring solution to the hair to be treated.
The present hair coloring composition is useful in the dispensers of the type disclosed in the aforesaid hair product applicator of U.S. Pat. No. 5,964,226 and to meet its unique requirements, but can also be applied in other ways particularly for touching up the roots of growing hair which was previously dyed with a permanent (e.g., oxidative hair dye), for highlighting hair, and for coloring sections of hair.
The hair dyeing composition of the present invention comprises a cationic semipermanent dye. Particularly suitable dyes are capable of capillary flow when in solution. Such dyes typically include azo dyes, diphenyldiamine dyes or quinoneimines containing a quaternary ammonium group, anthraquinones and nitro dyes, they are generally free of or contain a low concentration of foaming agents such as surfactants or detergents. They suitably have a controlled, nearly free-flowing viscosity, such as in the range of from about 10 to about 200 cps to be nearly but not quite free flowing and yet not drip or cause a buildup on the hair. The semipermanent dye composition is dissolved in a liquid vehicle which has a controlled vapor pressure for a predetermined rate of evaporation, i.e. a controlled rate of drying. The dye compositions of the present invention can optionally also contain a clear polymeric dye-shield anti-ruboff component to prevent the transfer of the applied color from the hair to surfaces such as pillows, clothes, etc., such as a polymer of vinyl acetate and of vinyl pyrrolidone, or a copolymer thereof which has been found to be particularly effective for that purpose.
The composition of the present invention must meet various requirements to be suitable for use in a hair dye applicator with a capillary flow or other type of applicator which applies it to the hair through direct contact therewith, for coloring hair roots, highlighting and section coloring of hair. The method of the present invention involves applying the hair dye composition of the present invention through an applicator to the hair, wherein the material of the applicator tip hair contacting surface is substantially saturated with the semipermanent hair dye composition of the present invention. The applicator can be that of the aforesaid U.S. Pat. No. 5,964,226, or a sponge or a wad of cotton or an absorbent dipstick or pen-type applicator.
The composition suitably contains a semipermanent dye capable of retention through a number of shampoos. It must flow through the applicator without clogging it. It should be capable of instantaneous application upon touching the hair and it must not drip. The dyes should be capable of penetrating the cuticle of the hair in a level fashion without leaving an undesirable coating. It should suitably be non-foaming and should be at least somewhat quick drying. The dye composition can also optionally contain a shielding antiruboff component to safeguard against color being transferred from the hair to pillows and other surfaces. It should have a sufficiently, low viscosity so that the composition flows easily from the applicator to the hair surfaces contacted thereby, and should have a suitable pH to allow the desired degree permanence on the hair.
A principal feature of the present invention is the use of a hair substantive semipermanent dye. Suitable dyes are generally water or alcohol soluble, and are safe for use on human hair. There are many dyes that tend not to flow through a wick and capillary applicator and tend to clog the system. The ratio of water and alcohol or other volatile solvent can be varied in the vehicle of the hair dye composition to obtain a predetermined rate of evaporation thereof. The total solvent (e.g. water plus volatile solvent) can be up to 95% (wt) of the dye composition. Butyl cellosolve or alcohol proportion in the vehicle can be varied up to 50% of the solvent with a proportionally lower concentration of water, when a higher rate of evaporation is desired. The appropriate proportions of water and the more volatile solvent can be determined by routine experimentation to obtain the desired evaporation rate.
Particularly suitable semipermanent dyes include azo dyes, diphenylamine dyes, quinone-imines containing a quaternary ammonium group, anthraquinones and nitro dyes.
The dyes are moreover capable of being instantly deposited on the hair. They allow for repeated touching to the hair with increased coverage upon each application. They penetrate the hair shaft leaving a clean, non-messy level of color molecules on the hair. No unsightly mess is left on the hair or scalp on drying.
While the dye composition can contain a small amount of suitably cationic or nonionic surfactant, its concentration should be low to avoid it from foaming. Level application can be promoted by the use of an alcohol solvent system, e.g., ethyl alcohol, isopropyl alcohol or a butyl alcohol.
Quick drying with a safe and clean solvent was realized with an alcoholic system such as with ethyl alcohol. It has a pleasant odor and works with water to evaporate at a faster rate than water alone. Isopropyl alcohol can also be used but it has a less desirable odor. Butyl alcohol, such as a tert butyl alcohol butylene glycol, 2-butanol, or butoxy ethanol (butyl cellosolve) is also suitable as solvents for direct dyes and to improve penetration into the hair shaft.
The optional protective ruboff shield component provides against ruboff of the color to objects coming into contact with dyed hair, e.g., pillow cases, clothing, etc. The polymeric ruboff shield should not interfere with the coloring process. The polymer used in the present composition is compatible with the hair while forming a ruboff shield that surrounds each hair shaft and is gradually removed upon each subsequent shampooing. Polyvinylpyrrolidone alone or copolymers of vinyl acetate and vinylpyrrolidone monomers are particularly effective to serve this purpose, because they are not tacky and do not interfere with the free capillary flow of the dye liquids. Generally 50% solutions of these copolymers are sold by ISP Corp., and by BASF. Most or all nonionic or cationic polymers are likely to work, and many others can be identified by routine experimentation. Anionic polymers are not expected to work.
The viscosity of the composition to be used is important to be free-flowing and yet not drip or cause a build-up on the hair. Systems using standard thickening agents such as gums are not successful. However, a slight amount of a thickener such as a carbomer or a cellulose can be used especially to prevent a too rapid runoff from the applicator. A viscosity in the range of 10-200 cps, has been found to meet these requirements, more suitably between 10 and 100 cps to be sufficiently flowing.
It has been found that the composition for hair coloring should be at a pH from about 8 to about 8.5 for best semi-permanent coloring of the hair, however, the most suitable pH will also depend on the identity of the dye and its host substantivity, as will be readily known to the skilled hair colorist.
Some dyes, such as some nitro dyes, e.g. HC yellow #2, are not well or completely soluble in the aqueous alcoholic solvent. In that case the use of an additional solvent may be needed. For example butoxyethanol (butyl cellosolve) can be suitably substituted for some (e.g. 10%) of the water.